The use of tufting machines to create tufted articles, for example tufted carpet, is well known in the art. Conventional tufting machines use a reciprocating needle bar carrying a plurality of aligned needles thereon, the needles being arranged into a row, or rows of needles carried on the needle bar, the needles being constructed and arranged to reciprocally penetrate a backing material passing transversely underneath the needle bar and passing over an adjustable bed plate. The bed plate may be adjusted with respect to the needles for increasing or decreasing the height of the tufted piles so created. As the needles penetrate the backing material, they carry a filament of yarn therethrough, whereupon the yarn is caught either by a looper positioned with respect to the needle to create a looped pile of yarn, or by a hook moving in timed relationship with a knife to create a cut pile of yarn. It is by these well known processes, for example, that loop pile and cut pile tufted carpeting is made.
Early tufting machines typically used a single row of aligned and spaced needles mounted on a single needle bar, in conjunction with either a single looper or a hook/knife combination for each such needle, to create either a loop pile or cut pile tufted article. As known to those of skill in the art, the needles used in tufting machines have a take-off hand which is formed by a target and an adjacent yarn pickup area defined on one side of the needle. It is against the target and the yarn pickup area that the bill of a looper, or hook, will slidingly pass, above the eye of the needle, to catch the yarn in the throat of the looper or hook, respectively, such that when the needles are withdrawn backward through the backing material on a backstitch, a loop of yarn, a tuft, is retained with respect to the backing material. The looper or hook which engages the appropriate target and/or pickup area, will have a corresponding take-off hand. Therefore, if the needle has a right take-off hand, the looper will be provided with a bias point having a right take-off hand such that the left leading edge of the looper will strike the target area on the right side of the needle and slide up over the target area and onto the pickup area to hook or loop the tuft of yarn prior to the needle moving upward and back through the backing material on the backstitch.
In a large majority of tufting machines, all of the needles will have a common take-off hand as will the loopers. Due to the fact that the loopers engage, i.e. strike, the take-off areas of their respective needles, the loopers will tend to deflect in that direction so that a right hand take-off looper striking a right hand take-off needle will tend to be deflected to the right of the needle due to the mechanical interaction of the looper as it goes through a rocking motion with respect to the needle at its bottom dead center position.
Also, and as well known, tufted articles may be produced in a range of gauges, the gauge being equal to a number of gauging elements, for example, needles, loopers, hooks/knives, or even reeds, extending along a predetermined gauging length, the gauging length being a predetermined unit of length, for example divisions of an inch, extending across a portion of the width of the tufted article being produced. An eighth gauge machine, therefore, would have eight gauging elements, for example, needles, extending along the width of a single gauge distance, i.e. eight needles per inch.
Tufting machines having a gauge of one tenth of an inch or less are considered to be "close" or "narrow" gauge machines, in that the gauging elements are, of necessity, fit closely with respect to one another within the predetermined gauge distance. For example, and in contrast to an eighth gauge machine, a sixteenth gauge machine will have sixteen gauging elements, twice the number of gauging elements of an eighth gauge machine, extending along the same predetermined gauge length of a gauging block or bar, for example. This results in a very close spacing of the gauging elements with respect to one another, and oftentimes requires that these gauging elements be made much smaller than are larger gauge needles and loopers, or hooks/knives, so that the requisite spacing exists between gauging elements to allow the loopers and yarns to freely pass between the needles during tufting. However, in close gauge machines, not only are the gauging elements themselves constructed to be finer, but the yarns themselves must also be finer, i.e., of smaller diameter, all of which costs more money to manufacture due to the more exacting tolerances and relatively minute size of each of these gauging elements, and yarns, respectively. Smaller diameter yarns also tend to be more fragile, and thus are more prone to being accidentally cut.
On the other hand, an eighth gauge machine provides twice the spacing of a sixteenth gauge machine within the same gauge distance, thus allowing for the use of larger needles which are easier to manufacture and which cost less to make, and the use of larger yarns, which also cost less to manufacture, as well as the use of larger loopers and/or hooks/knives, which are also easier to manufacture and also cost less. Another advantage of larger gauge machines is that a lower number of stitches are required per unit length of the tufted article in order to provide an adequate face weight of the tufted article, whereas a close gauge machine requires a greater number of stitches in order to provide the same weight of yarn along the same unit length of the tufted article. For example, in order to achieve a desired weight, an eighth gauge machine may only require six stitches per inch, whereas a sixteenth gauge machine may require somewhere in the range of from twelve to fourteen stitches per inch to provide the same face weight of the finished tufted article.
Moreover, during the tufting process, as the yarns are passed by the needles through the backing material, in conjunction with whether the respective yarns are being fed to the needles by either a front or a rear yarn feed device, the yarns tend to take on a yarn twist such that the penetration of the needles and yarns through the backing material, and the withdrawal of the needles backward through the backing material on the backstitch as the yarn is held in position by a hook or loop, tends to impart a discernible twist to the yarns in the face of the tufted article. Accordingly, when right hand take-off needles and loopers are used, the yarns will have a tendency to twist in a common direction. This is not a significant problem in large gauge tufting machines as the yarns are relatively large, and tend to bloom up to fill the space between the adjacent rows of the yarns such that a uniform finished surface appearance of the tufted article is provided. However, when close gauge machines are used, the use of finer yarns results in the likelihood that a gap between rows of tufted material may be present due to the yarn twist.
As tufting machines have evolved, the use of dual needle bar machines, in which each needle bar laterally shifts with respect to the other, known as a "graphics" type of tufting machine, has developed. An example of such a machine is disclosed in U.S. Pat. No. 4,366,761 to Card, issued Jan. 4, 1983. These tufting machines use a needle for shifting device for each needle bar to shift the needle bars, with respect to one another, for example in opposite directions, or in timed relationship with respect to one another to form a graphic pattern or design in the face of the tufted article. An example of a needle shift device used with this kind of machine is disclosed in U.S. Pat. No. 4,440,102, to Card et al., issued Apr. 3, 1984.
In these dual needle bar machines, a first series of gauging elements, for example a first, front row of needles, will be mounted on the first needle bar, each of the gauging elements having a first gauge, for example, an eighth gauge spacing of the needles. The second needle bar will be provided with a second, rear series of needles, which may be of the same, or a differing gauge with respect to the first series of needles. Both series of needles, however, may be of the same take-off hand, such that if each needle had a right take-off hand, the yarns tufted by each row of needles will tend to lean to the right with the result that the yarns that are taken off from the front row of needles will lean to the right, whereas the yarns taken off of the rear row of needles will tend to lean to the left if a right hand take-off needle is used on both the front and rear series of needles. In larger gauge machines, for example anything greater than tenth gauge, this problem is minimized due to the size of the yarns. However, with close gauge machines, this use of the same hand tufting gauge elements on both the front and rear needle bars tends to accentuate the yarn twists such that any gap between the yarns may become more apparent.
Also, even though a pair of shifting needle bars may be used, a close gauge dual shifting needle bar machine still requires more stitches per inch in order to achieve the same face weight of the tufted article as does a dual needle bar machine having larger gauge needles using larger diameter yarns. Additionally, when using finer yarns in close gauge machines, these yarns tend not only to be more expensive to produce, but also are more likely to break or cut if pinched during the tufting process, and will not bloom after tufting to the extent a larger diameter yarn will.
One approach to obtaining a higher quality tufted article on dual shifting needle for machines has been to use gauging elements of an opposite hand on each respective needle bar, so that, for example, the front needle bar will have needles of a right take-off hand, and the rear needle bar will have needles of a left take-off hand. When the tufting operation is being performed, therefore, the yarns of the first and second series of needles will tend to lean in the same direction, thus minimizing the problems of gaps between adjacent rows of tufts due to yarn twist. Again, this problem is less pronounced when using larger diameter yarns than it is when using smaller diameter yarns. Another approach which is known in the art is to use a "semi-modular" looper block assembly in a non-casted arrangement having two series of loopers which are manually mounted and aligned, and with each series having opposite takeoffs with respect to one another. This looper assembly comprised a rectangular steel block with slots for individual loopers to be manually inserted, with detents holding the loopers in place. A square channel was broached through the semi-modular block, which itself was mounted to a staff that was located into a looper guide bar. These loopers were designed to cooperate with needles of opposite takeoffs. This arrangement, however, nevertheless relied upon a configuration including loopers held in place by detents, which necessarily included the inherent problems of a non-casted module.
It has also been known in the use of tufting machines to position and set each gauging element separately within the appropriate gauge bar, and to hold the elements in position with set screws or the like. Due to the difficulty inherent in positioning each respective needle or looper by hand within the appropriate gauge bar, for example a needle bar or a looper gauge bar, however, and then securing the gauging element with a set screw, the use of cast gauging modules or blocks has been developed in which a cast modular gauge block is produced having a sufficient number of gauging elements, be they needles or loopers, embedded therein. These modular gauge blocks offer the advantages of uniform and consistent gauging element spacing, and are easier to remove and replace than are the gauging elements themselves, when done separately in accordance with past practice. An example of this type of gauging module is disclosed in U.S. Pat. Nos. 5,295,450, and 5,400,727, issued to Neely on Mar. 22, 1994, and Mar. 28, 1995, respectively.
One problem that arises with the use of close or narrow gauge gauging elements on a dual shifting needle bar machine, where all of the gauging elements are of a common take-off hand, either a right or a left hand take-off, is that as a higher number of gauging elements is present along the predetermined gauge length, for example sixteen needles in a sixteenth gauge machine, which requires a looper block having at a minimum sixteen loopers along its length, the bills of the loopers are rocked toward and into engagement with the respective needle with which each such looper is associated, the loopers will tend to deflect in a common direction, between the needles to the right side, for example, which oftentimes can result in binding between the needles and loopers, or pinching the yarns therebetween due to this deflection, especially if the gauging elements are "oversized." If larger diameter yarns are used, the loopers will likely break or cut the yarns passing between the needles during the tufting process. This may also result in damage to the gauging elements themselves, whereupon the tufting machine must be shut down and the damaged gauging elements repaired or replaced, or yarns rethreaded and tied off, all of which greatly slows production rates and increases production costs. Even with the use of gauging modules, this problem still persists.
What is needed, therefore, is an improved tufting machine gauging element configuration in which larger gauge and easier to manufacture gauging elements of a gauge larger than the machine gauge, may be used in a close gauge machine. In particular, there is a need for an improved gauging element configuration in which the larger gauge needles of the front row of needles, for example, can be passed between the individual loopers of the rear series of loopers within a close gauge machine without binding or interfering with each other, and without otherwise cutting or breaking the yarns. There is also a need for an improved gauging element configuration in which the results of using larger gauging elements and larger diameter yarns can be attained, and which provide the benefits of a close gauge machine and the patterns and designs unique to close gauge machines in conventional tufting machines using larger diameter yarns at increased stitch rates and at increased production rates.
What would be desirable, therefore, but remains unattainable in the known art, is a dual shifting needle bar tufting machine using opposite hand gauging elements, for example needles and loopers, of a large gauge combined together into a close gauge, such that larger gauge gauging elements and larger diameter yarns can be used in a close gauge machine. What is also needed, but unavailable in the art, is a close gauge tufting machine using opposite hand gauging elements of a larger gauge on a dual shifting needle bar tufting machine in which the gauging elements, and in particular the loopers, will allow the large gauge needles of the front row of needles to penetrate the rear row of loopers without binding or interfering with one another, and which will also not tear or cut the large diameter yarns used in such a tufting operation.